# Matter 1.6.1 targets staggered lights and noisy chimes

Matter 1.6.1 makes Groupcast certifiable and adds optional chime mute and volume controls, but current products and platforms still need updates.

Canonical page: https://matterhome.io/news/matter-1-6-1-groupcast-chime-controls
Markdown page: https://matterhome.io/news/matter-1-6-1-groupcast-chime-controls.md
Author: Matterhome Editorial Team
Author profile: https://matterhome.io/authors/matterhome-editorial-team
Editorial lead: JC Martinez
Editor profile: https://matterhome.io/authors/jc-martinez
Published: 2026-09-27T02:06:32.000Z
Category: Standards update
Tags: Matter, CSA, Smart home platforms, Doorbells

## Feature Image

- Origin: sourced
- Image: https://assets.matterhome.io/content/news/2026-09-27-matter-1-6-1-groupcast/feature.6758edc6bf9bcbbe5864/source.webp
- Alt text: Official Matter smart home graphic from the Connectivity Standards Alliance
- Caption: Official CSA Matter graphic reused from Matterhome's local standards coverage.
- Source: https://csa-iot.org/all-solutions/matter/

## Sources

- https://csa-iot.org/developer-resource/specifications-download-request/
- https://csa-iot.org/wp-content/uploads/2026/09/23-27351-011_Matter-1.6.1-Device-Library-Specification.pdf
- https://github.com/project-chip/connectedhomeip/releases/tag/v1.6.1.0
- https://github.com/OpenHomeFoundation/roadmap/issues/216

The Connectivity Standards Alliance accepted the [Matter 1.6.1 specification](https://csa-iot.org/developer-resource/specifications-download-request/) on September 16, 2026, and the official Matter SDK followed on September 25. This maintenance release moves Groupcast out of the provisional list and gives doorbell chimes an optional path for separate sound controls. It does not update a light, switch, hub or chime already in your home.

The practical Groupcast target is a room where several Matter lights respond one after another instead of together. The [Matter 1.6.1 device library](https://csa-iot.org/wp-content/uploads/2026/09/23-27351-011_Matter-1.6.1-Device-Library-Specification.pdf) now defines Groupcast sender and listener requirements for relevant device types. A compatible controller can send one secure multicast command to the group rather than addressing each device in sequence, reducing the visible stagger often called the popcorn effect. It is still an implementation path, not a promise that every existing Matter light group will suddenly behave better. Controllers, devices and their firmware need matching support.

## Home Assistant shows the remaining gap

The Open Home Foundation has a [Matter 1.6.1 Groupcast project](https://github.com/OpenHomeFoundation/roadmap/issues/216) marked as building. Its stated plan is to add native Matter group management and test one-to-many commands across brands and Thread network sizes. No finished Home Assistant release is named there yet.

The [official SDK release](https://github.com/project-chip/connectedhomeip/releases/tag/v1.6.1.0) gives implementers the current data model and Groupcast changes, but an SDK tag is not a consumer rollout. Matterhome has not tested Groupcast, and Apple Home, Google Home, Alexa and SmartThings have not established support for this 1.6.1 behavior in the sources checked for this article.

## Chimes can separate sound from light

Matter 1.6.1 also revises the Chime device type. A chime may now include a Speaker endpoint for volume and mute controls. Muting that sound endpoint can leave another alert, such as a flashing light, active. Disabling the whole Chime remains a separate action that can also stop its visual indication.

The Speaker endpoint is optional. A Matter 1.6.1 label alone will not prove that a particular doorbell chime exposes volume, mute or visual-alert controls in your preferred app. The device maker and controller platform still need to document those features for the exact model and firmware.

For now, buy grouped lights and doorbells for the behavior their support pages describe today. Test a multi-light room before expanding it, and choose a doorbell for its current chime controls rather than an expected Matter update. Matter 1.6.1 makes both experiences easier to build. It does not make them available by itself.